1. Field of the Invention
The present invention relates to an EL display device and a method for manufacturing the same.
2. Description of the Related Art
In full-color electroluminescent (hereinafter referred to as “EL”) display devices that are required to be of high definition and small size in applications such as being mounted in small devices such as mobile devices, the size of individual pixels is reduced, and it is thus difficult to color an EL layer as a light-emitting layer in different colors so as to emit different colored lights in respective pixels. Therefore, an EL display device of color filter type has been proposed.
In such a type of EL display device, full-color display is realized by providing a common white light-emitting layer that straddles all pixels, and disposing color filters above the white light-emitting layer, as disclosed in, for example, JP 2002-299044 A.
In the manufacture of a so-called planar display, in general, a method is widely performed, for reducing the cost and lead time per product, in which a number of display devices are previously made on a large-sized glass substrate called a mother glass in manner of so-called gang printing (by which multiple pieces are obtained from one substrate) and the mother glass is cut after the end of the process to obtain a number of individual display devices.
When the mother glass is cut after a number of display devices are made with the light-emitting layer formed so as to straddle the entire surface of the mother glass, the light-emitting layer is exposed to the outside at the cut plane. An EL material used for the light-emitting layer is unstable to moisture or oxygen, and therefore, the light-emitting layer is deteriorated due to the moisture or oxygen entered from the exposed portion.
The invention has been made in view of the points described above, and it is an object of the invention to prevent the deterioration of a light-emitting layer in a color filter type EL display device, enable the manufacture of the EL display device by a gang-printing method, and reduce the cost in manufacture.